Learning Java, 4th Edition

Filling Shapes

Iguana fills its shapes with a number of colors, using the setPaint() method of Graphics2D. This method sets the current color in the graphics context, so we set it to a different color before each drawing operation. setPaint() accepts any object that implements the Paint interface. The 2D API includes three implementations of this interface, representing solid colors, color gradients, and textures.

Solid Colors

The java.awt.Color class represents color in Java. A Color object describes a single color and implements the Paint interface for filling an area with it. You can create an arbitrary Color by specifying the red, green, and blue values, either as integers between 0 and 255 or as floating-point values between 0.0 and 1.0. The (somewhat strange) getColor() method can be used to look up a named color in the system properties table, as described in Chapter 11.

The Color class also defines a number of static final color values; we used these in the Iguana example. These constants, such as Color.black and Color.red, provide a convenient set of basic color objects for your drawings.

Tip

Excessive creation of redundant color instances is a common cause of memory bloat in Java clients. Consider using a factory pattern to ensure you don’t have 200 instances of periwinkle.

Color Gradients

A color gradient is a smooth blend between two or more colors. The GradientPaint class encapsulates this idea in a handy implementation of the Paint interface. All you need to do is specify ...